In wireless communication, information is transmitted using a radio communication channel. For performing the transmission, a useful signal including the information is modulated on an HF carrier for generating a modulated HF signal and fed into the radio communication channel by way of an antenna. The modulated HF signal propagates through the radio communication channel and is received as an HF reception signal by a receiver device. The receiver device is arranged to process the HF reception signal for recovering the useful signal.
Through current trends in mobile communications, the industry is faced with the demand for applications with a high data rate. These may be, e.g., video telephony, video or network games, streaming multimedia, web browsing, and others. Consequently, telecommunication devices are arranged for multi-band and/or multi-mode operation. Within the UMTS (universal mobile telecommunication system) or W-CDMA (wideband code division multiple access) standards, communication standards allowing for transmission at high data rates are being developed, such as HSDPA (high speed downlink packet access) or HSUPA (high speed uplink packet access). Other standards are defined by WLAN (wireless local area network) in IEEE 811.11 or by WIMAX.
Usually, high data rates necessitate good signal quality in a receiver device, i.e., a relatively high signal-to-noise ratio (SNR) in a receiver chain of both a terminal, such as a mobile telephone, and a base station. With increasing distance between a transmitter device and a receiver device, the HF reception signal may become distorted with respect to the modulated HF signal.
If the terminal is near the edge of a cell surrounding a base station, the reception quality in the receiver device is limited by thermal noise and a noise figure of the receiver device itself. Furthermore, the HF reception signal is distorted by a noise figure of the radio communication channel caused by mechanisms such as Rayleigh fading, thermal noise of other electronic devices, technical noise, e.g. caused by motor vehicle ignition, any natural noise, e.g. discharges, such as lightning, and others.
One possible solution for achieving a high data rate would be to increase the number of base stations to minimize the maximum distance between a terminal device and a base station. However, this necessitates much financial investment in base station infrastructure.
Another possible solution is to increase the number of reception paths in the receiver device. As a result, a more accurate reconstruction of the useful signal can be achieved. This concept is also referred to as a “diversity receiver.” A diversity receiver usually necessitates a number of internal devices in the receiver chain, and it is desirable to reduce this number to allow for a simpler and more inexpensive architecture of a diversity receiver.